Minimizing odor by adding methylol amides and methylol amines to reducing agent solutions used to treat wool



United States Patent 3,519,383 MINIIVHZING ODOR BY ADDXNG METHYLULAMIDES AND METHYLGL AMINES T0 RE- DUCING AGENT SOLUTEGNS USED T l) TREATW091,

Earl Peters, Spartanbnrg, S.C.., assignor to Bearing Milliken ResearchCorporation, Spartanburg, S.C., a corporation of Delaware No Drawing.Continuation of application Ser. No.

283,565, May 27, 1963. This application Aug. 27, 1968, Ser. No. 764,008

Int. Cl. D06rn 3/06, 3/08 US. Cl. 8-127.6 Claims ABSTRACT OF THEDISCLOSURE Formaldehyde and formaldehyde-generating compounds are usedin the modification of keratinic fibers with reducing agents to inhibitfiber odor.

This application is a continuation of application Ser. No. 283,565,filed May 27, 1963 and now abandoned.

This invention relates to processes for eliminating the odor associatedwith keratin fibers which have been treated with reducing agents and tokeratin fibers resulting from such processes.

Fabrics containing keratin fibers, particularly wool fabrics, have beentreated with reducing agents for the purpose of setting the fabrics in agiven configuration. Wool fabrics treated with reducing agents can, forexample, be set in a creased configuration which is substantiallydurable to wetting. This treatment has been utilized to improve fabricscontaining wool fibers in many ways, e.g., to impart durable creases,pleats, and/or fiat configurations to wool fabrics, to impart to thesefabrics a propensity for such setting operations, to elasticize woolfabrics and for many other purposes.

Fabrics treated with reducing agents, however, have a characteristic,unpleasant odor. The cause of the odor is unknown. It is not believed tobe related to the sulfur content of many reducing agents utilized in theabove processes since reducing agents which contain no sulfur atomscause the same unpleasant odor. It is believed that the odor is merelycharacteristic of wool which has been treated with a reducing agentwhereby disulfide linkages in the wool fiber are reduced to thesulfhydryl form. These sulfhydryl groups are generally believed to beoxidized during subsequent setting operations, although the fact thereofand the mechanism of the oxidation reaction has given rise to a numberof conflicting theories.

Regardless of the mechanism of the reaction of keratin fibers withreducing agents, however, the end product invariably is characterized byan unpleasant odor.

Many attempts have been made to solve this problem, particularly sinceprocesses which utilize reducing agents to improve properties of fabricscontaining keratin fibers have enjoyed increasing commercial success. Atypical technique involves the use of masking agents on reduced woolfabrics. These agents mask the reduced wool odor, but often impart tothe fabrics so-treated an odor which purchasers do not associate withnormal wool. Consequently, the fabric containing the masking agent isnearly as objectionable in odor as the untreated reduced wool fabric.Furthermore, these masking agents often are not durable to conventionaldry-cleaning techniques. It is particularly desirable that the reducedwool fabric be indistinguishable in odor from fabrics which have notbeen treated with reducing agents.

The odor problem associated with processes involving the use of reducingagents for modification of keratin fibers has been solved in accordancewith this invention 3,519,383 Patented July 7, 1970 by contactingreduced keratin fibers, having the characteristic unpleasant odor, withan aldehyde compound. The aldehyde may be applied as such or by way ofan aldehyde-generating compound which, upon heating or chemicalactivation, generates the desired aldehyde.

Formaldehyde and formaldehyde generators are the most readily availablealdehydes and are preferred for use in accordance with this invention.When the aldehyde is applied to finished fabric, i.e., fabric which hasundergone textile finishing operations, it is preferred that thealdehyde be derived from linear formaldehyde polymers, such asparaformaldehyde, which depolymerize upon heating to provide monomericformaldehyde vapors. The fabric is exposed to the vapors of thedepolymerizing polymer in this embodiment of the invention. The vaporshave little or deleterious effect on the fabric finish.

Typical aldehydes other than formaldehyde include saturated aliphaticaldehydes, such as acetaldehyde, propionaldehyde, butylaldehyde,isobutylaldehyde, valeraldehyde, isovaleraldehyde, caproaldehyde,enanthaldehyde, caprylaldehyde, pelargonaldehyde, capraldehyde,lauraldehyde, palmitic aldehyde, stearaldehyde and the like; unsaturatedaliphatic aldehydes, such as acrolein, crotonaldehyde, tiglic aldehyde,citronellal, citral, propiolaldehyde and the like; alicyclicmonofunctional aldehydes, such as formylcyclohexane and the like;aliphatic dialdehydes, such as glyoxal, malonaldehyde, succinaldehyde,glutaraldehyde, adipaldehyde, maldealdehyde and the like; substitutedaldehydes, such as chloral, aldol and the like; aromatic aldehydeswherein the aldehyde group is attached to a ring, such as benzaldehyde,phenylacetaldehyde, ptolualdehyde, p-isopropylbenzaldehyde,o-chlorobenzaldehyde, o-nitrobenzaldehyde, m-nitrobenzaldehyde,pnitrobenzaldehyde, salicylaldehyde, anisaldehyde, vanillin,veratraldehyde, piperonal, u-naphthaldehyde, anthraldehyde and the like;and aromatic aldehydes wherein the aldehyde group is not attached to aring, such as phenylacetaldehyde, cinnamaldehyde and the like; andheterocyclic aldehydes, such as ot-formylthiophene, a-formylfurfural,furfural, tetrahydrofurfural and the like.

Typical aldehyde generating compounds include linear polymers,particularly those of the general formula HO (CH O) -H whichdepolymerize to monomeric formaldehyde gas upon vaporization. In thisclass of compounds, there are included lower polyoxymethylene glycols,wherein n is from about 2 to about 8; paraformaldehyde, wherein n rangesfrom about 6 to about 100; alphapolyoxymethylenes, wherein n is greaterthan about 100; beta-polyoxymethylene wherein n is greater than about100 and a trace of H is present, and the like.

Polyoxymethylene glycol derivatives may also be utilized, e.g., such asthe polyoxymethylene diacetates, the lower polyoxymethylene dimethylethers, gamma-polyoxymethylenes (higher polyoxymethylene dimethylethers), delta-polyoxymethylenes, epsilon-polyoxymethylenes and thelike. In general, higher temperatures, e.g., up to about 200 C. areutilized to effect depolymerization of these derivatives. In manyinstances, depolymerization, with formaldehyde generation, is mostreadily effected by treatment with dilute alkali or acid to produce thecorresponding glycol which can then be hydrolyzed to formaldehydesolution.

Formaldehyde acetate (formals) may also be utilized. Preferred formalsare produced by reaction of formaldehyde with alcohols of the formula CH(OR) in the presence of an acid catalyst, wherein R is alkyl or aralkyl.These compounds hydrolyze to formaldehyde and the parent alcohol.Preferred formals include methylol and 1,3-dioxolane. The lattercompound hydrolyzes to formaldehyde and ethylene glycol and isparticularly preferred among this class of compounds when used inpresensitizing processes.

Additional suitable generating compounds include the various methylolcompounds, for example, methylolalkanolamine sulfites, such asN-methylolethanolamine sulfite, N,N-dimethylolethanolamine sulfite,N,N-dimethylolisopropanolamine sulfite and the like; methylol amides,such as N-methylolformamide, N-methylolacetamide, N-methylolacrylamideand the like; amines, such as hexamethylene tetramine,trimethylolmelamine and the like; and compounds such as the alkali-metalformaldehyde bisulfites, including sodium and potassium formaldehydebisulfites.

The above compounds may be utilized to eliminate the characteristic odorof keratin fibers which have been treated with any conventional reducingagents utilized for setting keratin fibers.

These reducing agents, which are well known in the art, include themetallic formaldehyde sulfoxylates, such as zinc formaldehydesulfoxylate; alkali metal sulfoxylates, such as sodium formaldehydesulfoxylate; alkali metal borohydrides, such as sodium borohydride andpotassium borohydride; alkali metal sulfites, such as sodium orpotassium bisulfite, sulfite, metabisulfite, or hydrosulfite; mercaptanacids, such as thioglycollic acid and its water-solu ble salts such assodium, potassium, or ammonium thioglycollate; mercaptans, such ashydrogen sulfide and sodiurn or potassium hydrosulfide; alkylmercaptans, such as butyl or butyl or ethyl mercaptans and mercaptanglycols, such as beta-mercaptoethanol; ammonium bisulfite, sodiumsulfide, sodium hydrosulfide, cysteine hydrochloride, sodiumhypophosphite, sodium thiosulfate, sodium dithionate, titanous chloride,sulfurous acid and the like and mixtures of these reducing agents.

In practice, these reducing agents are applied to fabrics containingkeratin fibers, after which the fabric is set in a durableconfiguration, e.g., creased, pleated and/or flat,

by means of heat and/or pressure. In a typical durable creasingoperation, a solution of the desired reducing agent is sprayed to about40% pickup onto the fabric just prior to pressing, after which the wetfabric is pressed on a Hoffman press. After drying in the creasedconfiguration, the fabric crease is durable to subsequent wetting.

Fabrics may be treated with reducing agents at the mill level to impartthereto a propensity for subsequent durable setting. These treatmentshave become known as presensitizing processes, whereby the fabric ispresensitized for subsequent durable setting. There are presently twotypes of presensitizing processes, namely, the type which requires thatwater be sprayed onto the fabric prior to the setting operation and thetype wherein water is not required. The former type process is known asa wet crease presensitizing process, the latter being known as a drycrease process.

In a wet crease process, the fabric is impregnated with reducing agentat the mill level, after which it is dried and given a finish under mildconditions, generally involving low temperatures. The fabric is thenshipped, cut into garments, sprayed with water to about 40% pickup,pressed on a Hoffman press and dried in the pressed configuration.

Dry crease processes have been provided by addition to the fabric at themill level a low molecular weight polyhydroxy compound or a swellingagent as set forth in U.S. patent applications Ser. Nos. 167,420, nowPat. No. 3,423,166 and 111,447, now abandoned, respectively. In theseprocesses, the additive is incorporated in the fabric along with thedesired reducing agent. For some reason, unexplained to date, theresulting fabric can be dried at higher temperatures without destroyingthe presensitization characteristics. More importantly, however, theresulting fabric can be set in a desired configuration without addinglarge amounts of water to the fabric. For that matter, no extraneouswater whatsoever need be added beyond the regain level of the fabric toobtain excellent, durable configurations.

By the term low molecular weight polyhydroxy compound is meant acompound containing more than one hydroxy group and preferably having amolecular weight no greater than about 4000. Of these compounds, the

most readily available and desirable compound, from the standpoint ofease of application, comprises ethylene glycol. A particularly preferredgroup of glycols includes the polyfunctional glycols having terminalhydroxyl groups separated by 2 to 10 methylene groups, including, ofcourse, the preferred ethylene glycol as well as trimethylene glycol,tetramethylene glycol, pentmethylene glycol, hexamethylene glycol,heptamethylene glycol, octamethylene glycol, nonamethylene glycol, anddecamethylene glycol, or such glycols as 1,2-propylene glycol,dipropylene glycol, 1,3-butylene glycol, diethylene glycol, polyethyleneglycol or the like.

Polyfunctional compounds containing more than 2 hydroxyl groups includethe polyfunctional alcohol glycerols such as glycerine, quintenylglycerin, diethylglycerol and mesicerin, as Well as trimethylol ethane,trimethylol butane, tris(hydroxymethyl)aminomethane and others. Glycolethers, such as the water-soluble or dispersi'ble polyethylene glycolsor polypropylene glycols having molecular Weights no greater than about4000 also provide satisfactory results when utilized in accordance withthis invention.

Urea constitues the most readily available and desirable swelling agent,although any other material which will swell wool fibers in aqueousmedium is suitable. For example, guanadine compounds such as thehydrochloride; formamide, N,N-dimethylformamide, acetamide, thiourea,phenol, lithium salts, such as the chloride, bromide and iodide and thelike are similarly useful.

The swelling agent or low molecular weight polyhydroxy compound may beutilized in any desired amount depending on requirements for particularfabrics. For example, as little as about 0.5 to about 1% of theadditives, based on the weight of the fabric, provides some improvement,although, in general, larger amounts, e.g., from about 3 to about 10% byweight provide noticeable improvement. Larger amounts of up to about 50%or higher may be utilized, of course, if the particular end usejustifies the increased chemical cost in the use of these additives.

The above processes have been improved so that presensitized fabricshaving desirably lustrous finishes can be provided. In this novel typeprocess, described in U.S. patent application Ser. No. 278,359, now U.S.Pat. No. 3,449,061, the fabric is impregnated with a reducing agentprecursor compound, finished by conventional mill finishing operations,and then exposed to a gaseous re ducing agent activator. In this manner,all wet procedures are conducted prior to application of the desiredfinish on the fabric. The finish is substantially retained since thegaseous activator does not disturb the finish. Furthermore, the keratinfibers of the fabric are not in a reduced state until after allfinishing operations have been completed, so that no extraordinary caremust be taken to avoid inducing high residual relaxation shrinkageproperties into the fabric.

Also, since the fabric is not presensitized until after exposure to thegaseous activator chemical, full finishing operations can be practicedto impart a high degree of finish to the fabric with no effectwhatsoever on the degree of presensitization.

It has also been discovered that fabrics produced in this manner can bedurably set without the addition of water prior to pressing. Thisproperty is obtained without the aid of additives such as set forthabove, although slightly improved results can be obtained if theseadditives are utilized.

By reducing agent precursor as utilized herein is meant a chemicalcompound which forms a reducing agent for keratin fibers upon reactionwith another chemical compound. It is generally preferred that theprecursor compound have a pH of about 7 or greater as a 1% solution inwater. Particularly suitable compounds include lower alkanolamines, suchas monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-

ethyl ethanolamine, N,N-dimethyl ethanolamine, N,N- diethy ethanolamine,N,N-diisopropyl ethanolamine, N- aminoethyl ethanolamine, N-methyldiethanolamine, npropanolamine, isopropanolamine, triisopropanolamine,n-butanolarnine, dimethylbutanolamine, dimethylhexanolamine,polyglycolamines of the general formula HO(C H O) RNH wherein x is apositive integer and R is alkyl, e.g., the compound where x=2 and *R=C Hand the like. These compounds readily form reducing agent compounds uponexposure to S0 gas and other activators.

While the above alkanolamines constitute the preferred embodiment of thereducing agent precursor compounds, additional compounds include otheramines, for example those characterized by the formula R(NH wherein x isa positive integer of from 1 to about 4 and R is alkyl (e.g.,ethylamine, hexylamine and the like); aryl (e.g., aniline, toluidines,benzidine, and the like); R 'ONH wherein x=l, and R is alkyl or aryl,(e.g., hydrazides, such as acetoyl hydrazide H CCONHNH butyrohydrazide,benzoylhydrazide, and the like); hydrazin'es of the formula R"NHNHwherein R is selected from hydrogen, alkyl, aryl, and the like; e.g.,hydrazine, methylhydrazine, phenylhydrazine and the like; piperazinecompounds, such as piperazine, homopiperazine, N-methyl piperazine,N-hydr0xyethyl piperazine, N-aminoethyl piperazine, N-phenyl piperazineand the like.

Additional suitable basic precursor compounds include alkalis, such asthe alkali-earth metal and alkali-metal compounds, including thehydroxides, carbonates, borates, phosphates, e.g., sodium hydroxide,potassium hydroxide, lithium hydroxide, strontium hydroxide, bariumhydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate,potassium bicarbonate, sodium borate, potassium borate, sodiumperborate, disodium monohydrogen phosphate and the like.

Additional reducing agent precursor chemicals include aldehydes,particularly formaldehyde and glyoxal, although other aldehydes aresuitable, e.g., saturated aliphatic adlehydes containing up to about 18carbon atoms, such as acetaldehyde, propionaldehyde, butyraldehyde,valeraldehyde, caproaldehyde, enanthaldehyde, nonaldehyde, palmiticaldehyde and the like; unsaturated aliphatic aldehydes, such asacrolein, crotonaldehyde, tiglic aldehyde, citral, propiolaldehyde andthe like; alicyclic monofunctional aldehydes, such as formylcyclohexaneand the like; aliphatic dialdehydes, such as glyoxal, pyruvaldehyde,malonaldehyde, succinaldehyde, glutaraldehyde, adipaldehyde and thelike; aromatic aldehydes, such as benzaldehyde, tolualdehyde,a-tolualdehyde, cinnam aldehyde, salicylaldehyde, anisaldehyde,phenylacetaldehyde, a-naphthaldehyde, anthraldehyde,pyrocatechualdehyde, veratraldehyde and the like; heterocyclicaldehydes, such as a-formylthiophene, a-formylfuran, and the like;dialdehyde starch, and other aldehyde carbohydrates and aldehydiccellulosic materials. These aldehydes are consumed in the reaction withthe reducing agent activator gas so that, for odor removal, it isnecessary to add an amount in excess of that which is consumed when oneof these aldehydes is used as a reducing agent precursor.

It has also been discovered that ammonia per se can be utilized as areducing agent precursor, e.g., in combination with S0 or N 0 activatorgases. Ammonia may be provided as a gas, preferably anyhydrous, or asammonium hydroxide, methylammonium hydroxide, ethylammonium hydroxideand similar compounds. When applied as a gas, it may be applied before,after or during the desired finishing operation.

The procedure of applying the ammonia to the fabric after finishing, andbefore or after application of the activator gas is highly preferred forits simplicity and for the excellent results which are obtained Withouta wet finishing operation, which involves the added expense of paddingand drying. In addition, ammonia gas may be utilized in combination withother reducing agent precursors. For example, a wool fabric can beimpregnated With an alkanolamine, finished, and then exposed to bothammonia and S0 gases. This technique provides particularly excellentpresensitization in that better creases, or other configurations, ofimproved durability can be accomplished in this manner.

On the other hand, ammonia may be utilized as a reducing agent activatorper se, particularly in combination with nitrites to form ammoniumnitrites, ammonium complexes and the like.

As noted above, the reducing agent precursor, except for ammonia gas, ispreferably applied to the fabric prior to finishing in that thesecompounds are most conveniently applied to the fabric in liquid mediawhich would substantially destroy the finish on the fabric. Most of theprecursors are soluble in water and can be applied to the fabric asaqueous solutions, although dispersions, emulsions and other systems aresuitable. Uniform impregnation of the fabric is readily accomplished byconventional techniques, such as padding, spraying and the like. Itshould be appreciated, however, that the precursor chemical may beapplied in gaseous form before or after finishing if the practitionerprefers to volatilize the normally liquid precursor systems.

By reducing agent activator as utilized herein is meant a chemicalcompound, preferably in a gaseous state, which can react with one of theabove reducing agent precursors to form a different chemical compoundwhich is a reducing agent for keratin fibers, i.e., is capable ofrupturing the disulfide bonds of the keratin fiber molecular structure.It is not known with certitude if a reducing agent per se is formed insitu on the keratin fibers being treated, although the formation thereofis highly probable since both precursor and activator are consumedduring the treatment and cannot be washed out of the fabric in theirpre-treatment form.

Most of the preferred activator gases are reducing agents for keratinfibers and it is possible that the pretreatment of the fibers with oneof the precursor chemicals may merely sensitize the fibers for moreefficient reaction of the keratin fibers with the reducing agent gas,whereby presensitization of the fibers for subsequent durable setting iseffected.

Regardless of the mechanism of the presensitization, however, thereducing agent precursor chemicals and the reducing agent activatorgases can react in the absence of keratin fibers to form differentreducing agent compounds. Furthermore, presensitization is effected bythe process of this invention where treatment with a reducing agent perse is essentially ineffective for such purpose. For example, excellentpresensitization of keratin fibers for subsequent durable setting in theabsence of large amounts of water is effected by the process of thisinvention wherein the fabric is first impregnated withmonoisopropanolamine, subjected to the desired finishing operation andthen exposed to S0 possibly to produce monoisopropanolamine sulfite insitu on the fabric. On the other hand, if monoisopropanolarnine sulfiteper se is utilized, no such presensitization is effected and a durablecrease could only be obtained by pressing the fabric while it is wetwith large quantities of water, e.g., on the order of 40% by weight ormore. Similarly, treatment with S0 gas alone is generally ineffective inproducing a fabric presensitized for subsequent durable setting, with orwithout large amounts of water.

Since sulfites are generally excellent reducing agents for keratinfibers, S0 is a highly preferred reducing agent activator gas. Othersuitable activator gases include, however, hydrogen sulfide; mercaptans,such as methyl mercaptan (B.P. 6 C.), ethyl mercaptan (B.P. 37 C.) andthe like; mercaptan alcohols, such as Z-mercaptoethanol (B.P. 5052 C. at10 mm. Hg) and the like; nitrogen oxides, such as N 0 and the like;phosphorus-containing gases, such as phosphine and the like; nitrosatingagents, such as NOCl, NOBr and the like.

The amount of reducing agent precursor and activator gas can be readilydetermined by one skilled in the art depending on the fabric beingtreated and the extent of presensitization desired.

The preferred precursor chemicals are fairly strong bases. Keratinfibers tend to degrade considerably during prolonged storage under basicconditions. It is preferred, therefore, that a sulficient amount of thereducing agent activator gas, which generally is acidic, be utilized forsubstantially complete reaction with the precursor chemical or untilsubstantially neutral fabric is produced. Obviously, the fabric may beshipped under slightly acidic or basic conditions, or even under highlyacidic or basic conditions, but the optimum degree of physicalproperties in combination with the presensitized characteristic isobtained when the fabric is shipped essentially neutral.

In this regard, the fabric treated in accordance with this invention hasa higher degree of creasability after prolonged storage than fabricstreated by previous techniques. In fact, the performance of the fabricafter storage is generally superior to the performance immediately aftergassing. Consequently, conventional storage time has become an assetrather than a liability in the present presensitizing technique.

Fabric containing the precursor chemical may be exposed to the gaseousactivator in conventional equipment. For example, steam boxes, decatingapparatus, beam and package dye machines, drying ovens and the like maybe utilized.

The aldehyde compounds of the present invention may be applied tofabrics treated by any of the above processes, before, during or aftersuch processes. In general, the amount of aldehyde compound utilizedwill be determined by the type fabric treated, the degree of reductionproduced by reducing agent treatment and the stage of the variousprocesses at which the aldehyde compound is applied. For example, if thefabric has been finally set in a desired configuration orpresensitization toward subsequent setting is not desired, an amount ofaldehyde compound should be applied to the fabric which eliminates thereduced keratin fiber odor. In this regard, an excess of aldehydecompound may be utilized if desired and the excess removed by heatingand/or washing the fabric.

Since there is no readily available technique for measuring the degreeof reduction of disulfide linkages of the keratin fibers treated withreducing agent, there is no clear way to prescribe what amount ofaldehyde compound should be added. Consequently, subjective tests areutilized. In the embodiment of the invention wherein previously setfabrics are treated, the fabric can be tested for odor after the odorremoval treatment is given. If an odor remains, additional aldehydecompound is applied. If the reduced keratin fiber odor is eliminated,but an aldehydic odor remains, the fabric may be heated or washed toremove the residual aldehydic odor without reinstituting the reducedkeratin fiber odor. This, of course, indicates that some reaction hastaken place and that this reaction is substantially irreversible evenunder conditions of heat and pressure.

A different problem arises when presensitization toward subsequentdurable setting is desired, since the odoreliminators of this inventionalso destroy presensitization. The best test for amount of aldehydecompound to be utilized again is subjective. For example, the aldehydecompound may be added to the fabric along with the presensitizingchemicals. After completion of the process, swatches of the fabric maybe tested for creasability and odor. The creasing test may be made withor without water depending on the type process being practiced. Ifbetter than the desired level of creasing is obtained and a moderatereduced keratin fiber odor remains, additional aldehyde compound may beapplied to the fabric. Conversely, if the crease performance is not ashigh as desired, less aldehyde compound should be utilized. In

either instance, the fabric can be re-run through one of thepresensitizing processes without deleterious effects. In the formerinstance, an aldehyde or generator thereof may be applied to the fabricwithout re-running it through the process.

While the above subjective tests are the types that invariably will beutilized for specific situations, some indication can be given as to theamount of aldehyde that should be utilized. Presensitization towardsubsequent durable setting has been produced when there is utilized fromabout 1 to about mole percent, most preferably from about 5 to about 20mole percent, of the aldehyde compound, based on the moles of reducingagent which are utilized in the treatment of the keratin fibers. In thegas type presensitizing process, the aldehyde may be based on thetheoretical number of moles of reducing agent which would be produced insitu from the amounts of reducing agent precursor and activatorcompounds which are utilized.

In any event, the above subjective tests should be utilized to deviseprocess limitations for specific fabric, reducing agent and equipmentconditions.

While the process of this invention is particularly adapted to fabricscomposed essentially of keratin fibers, particularly those composedentirely of wool fibers, it is also applicable to fabrics whereinsynthetic, natural, or other keratin fibers are blended with the woolcomponent. Other keratin fibers include mohair, alpaca, cashmere,vicuna, guanaco, camels hair, llama and the like. Preferred syntheticfibers for blending with these fibers include polyamides, such aspolyhexamethylene adipamide; polyesters, such as polyethyleneterephthalate; and acrylic fibers, such as acrylonitrile homopolymers orcopolymers containing at least about 85% combined acrylonitrile, such asacrylonitrile/methyl acrylate (85/15), and cellulosics, such ascellulose acetate and viscose rayon. Of the natural fibers which may beblended With the keratin fibers, cotton is preferred.

Furthermore, the fibers need not be in fabric form during treatment. Forexample, the process may be conducted on top, tow, roving, sliver, yarnand the like.

The process of this invention may be performed on woven, non-woven, orknitted fabrics of any type, dyed or undyed.

In the following examples, dry crease performance data are obtained frompresensitized fabric samples having dimensions of 4 /2 inches in thefilling direction by 6 inches in the warp direction. These samples arefolded in half with the fold parallel to the warp yarns. The samples arethen placed on a Hoifman press, the cover is closed and locked and thesamples are pressed with 30 seconds top steam and 30 seconds baking,followed by 10 seconds vacuuming.

The creased samples are then opened and placed in a standing water bathwhich contains a wetting agent and is heated to F. After 30 minutes thesamples are removed, folded along the original crease line and allowedto air dry. After drying, the creases remaining in the samples are ratedsubjectively by at least three observers, the crease ratings runing from1 (no appreciable crease) to 5 (very sharp crease).

EXAMPLE I The following aqueous pad solutions are prepared:

(A) 5 monoethanolamine sulfite+0.1% Synowet HR anionic Wetting agent.

(B) 10% monoethanolamine sulfite+0.1% Synowet I-IR anionic wettingagent.

(C) 12.8% monoethanolamine sulfite+0.1% Synowet HR anionic wettingagent.

(D) 12.8% monoisopropanolamine sulfite+0.1% Synowet HR anionic wettingagent.

(E) 12.8% monoisopropanolamine su1fite+20% ethylene glycol+0.l% SynowetHR anionic wetting agent.

Samples of an all wool fabric, Deering Milliken style number 8012worsted fabric, are padded with each of these solutions to the levelsshown in Table I. After drying in a relaxed condition on a Fleissnerdryer, the fabric samples are creased after wetting to 40% by weightwith water as set forth above to provide crease ratings as shown inTable I.

The creases of all the fabrics treated herein display excellentdurability to wetting at 170 F. In addition, however, each fabric samplehas the odor of reduced wool.

To remove this objectionable odor, each sample is hung in a closedcontainer over a 37% formaldehyde solution. The solution is heated to5060 C. and maintained at that temperature for two hours. Upon removalfrom the formaldehyde vapor-laden container, the samples are entirelydevoid of the characteristic reduced wool odor.

In addition the relaxation shrinkage of the fabric samples which areexposed to formaldehyde vapors is substantially less than beforeexposure to formaldehyde. For example, the fabric sample treated withsolution A above, before pressing, has a relaxation shrinkage of 3.9% inthe warp direction and 2.6% in the filling direction. After exposure toformaldehyde vapors, the corresponding values are 0.2 and 0.3%,respectively.

In another typical embodiment, the fabric treated by solution E, afterpressing and without formaldehyde exposure, has warp and fillingrelaxation shrinkage values of 4.0 and 3.8%, respectively. Afterformaldehyde exposure, these values are 1.9 and 2.0%, respectively.

Similarly, trouser legs made from the fabric treated by solution B havewarp and filling relaxation shrinkage values reduced to 0.8 and 0.2%,respectively, by exposure to formaldehyde vapor.

EXAMPLE II Fabric samples treated as in Example I are folded withpleating papers and steamed in a steam box for minutes with a priorwater spray to about 20% pick-up. The pleat ratings, obtained in thesame manner as the crease ratings for solutions A, B, C, D, and E,respectively, are 2.5 2.8, 2.8, 2.8, and 2.8, respectively. Thesefabrics similarly are characterized by the reduced wool odor.

The fabrics are placed on hangers and then hung in the steam box. A 37%formaldehyde solution is poured into the steam box and steam isadmitted, whereupon the steam becomes laden with formaldehyde. After 20minutes, the fabrics are removed from the steam box. Each fabric sampleis devoid of the reduced wool odor and, furthermore, is devoid of aformaldehyde odor.

EXAMPLE III Skirts made from the fabrics of Example II are pleated asset forth therein and hung in a steam box, where they are subjected tothe vapors of sublimed paraformaldehyde crystals at about 70 F. Afterone hour, any excess formaldehyde vapors are blown from the system.About 10 mol percent by weight of paraformaldehyde, based on thereducing agent is utilized. The characteristic reduced wool odor iseliminated by this treatment and no residual formaldehyde odor remains.

EXAMPLE IV To the following pad bath solution: 12.8%monoisopropanolamine sulfite 20% ethylene glycol 0.1% Synowet HR areadded the various formaldehyde generating compounds set forth in TableII. The amounts given for the formaldehyde generating compoundscorrespond to 5, 10, 20 and 50%, respectively, of the moles of reducingagent padded onto the fabric.

Samples of the worsted fabric of Example I are padded to approximatelywet pick-up with each of the resulting solutions, after which thesamples are dried at 200 F. in a mechanical convection oven. A lustrousfinish is imparted to the samples by steaming on a Hoffman press for 2seconds between standard decater leader fabrics, followed by vacuumpumping for 10 seconds. The fabrics are evaluated for odor both beforeand after creasing without a water spray. The control fabric issimilarly treated except that no formaldehyde generating compound isutilized.

The odor evaluations are conducted in an aluminum lined room in whichthe relative humidity is held to 45% 15% at 82 Fri-3 F. with a roomdehumidifier. Also, the air in the room is constantly passed through anelectrostatic precipitator which includes an activated carbon filter.

The fabric samples are placed in 6 x 8 inch round battery jars at 20%moisture content. These jars have ground edges and are covered with 8 x8 x inch plate glass covers. The samples are maintained under theseconditions for 2 days and are then evaluated individually by anodor-sensing panel of 10 persons on a scale of no odor, a very slightodor, a slight odor, a moderate odor, a heavy odor, and a very heavyodor.

TABLE II Dry Amount, Pressed Unpressed crease Additive percent odor odorratings Reduced control Heavy Heavy 5 Untreated control Very slight....Ver slight. 1. 0 Sodiurnl'onnaldehydebisulfite 0. 298 Moderate Moderate3. 3 Do 0. 578 Slight Slight 3. 5 D0 1.156 Slight to Slight to 3. 3

moderate moderate. D0 2.890 Slight 3. 8 Paraformaldehyde. 0.060 Veryslight.... Slight... 3.3 Do 0.120 Slight do 4.2 Do 0. 240 Very slight.....do 2. 7

to slight. Do 0.600 .....do Slight to 2.1

moderate. Hexamethylenetetramine 0.044 Slight Slight 3. 5 0. 088 doSlight to 3. 5

moderate. 0.176 Moderate Slight 2. 7 0. 440 Slight Very slight.-.. 3. 2

acetamide 0.169 Slight to Slight 3. 2

moderate. Do 0.338 Very Slight to ....do 2.6

slight. D0 0.676 .....do Very slight 3.4 Do 1. 690 Slight Very slight 3.0

to slight. N-methylol- 0.192 ..d0....... Slight to 3.2

aerylamide. moderate.

Do 0. 384 .....d0 Very slight 3. 0

to slight. Do 0.768 Slight to do 3. 1

moderate. Do 1.920 Moderate do 2.9 Trimethylol- 0294 Very slightSlight... 3.0

melamine, 80 percent.

Do 0. 588 Very Slight to Very slight- 3. 5 slight. Do 1.176 SlightSlight 2, 9 D0 2. 940 Moderate to Very slight to 3. 2

heavy. slight.

EXAMPLE V Samples of the fabric of Example I are padded to 70% pick-upwith an aqueous solution containing 6.4% monoisopropanolamine sulfite,0.1% Synowet HR and 0.120% of paraformaldehyde (1 mole ofparaformaldehyde per 10 moles of reducing agent utilized). In making upthe pad solution, the system is heated to F. with stirring to dissolvethe paraformaldehyde crystals. After ageing 1 l for 20 minutes, thefabric samples are dried relaxed in a Fleissner dryer, then semi-decatedat a cycle of 5 seconds steaming and 2 minutes vacuum pumping to obtaina lustrous finish on the fabric.

The odor of the fabric samples is evaluated as in Example IV both beforeand after pressing in a dry state on a Hoffman press. Only a very slightreduced wool odor remains, compared to the very heavy odorcharacterizing the control fabric which is similarly treated but withoutparaformaldehyde. No odor of formaldehyde can be detected in thesefabric samples.

EXAMPLE VI The reduced control fabric of Example V is cut and sewn intoskirts, pleated with conventional pleating papers and steamed in anautoclave for 20 minutes to set the pleats.

A moderately heavy reduced wool odor is readily detected in theseskirts. Paraformaldehyde crystals are placed at the base of theautoclave and heated, whereupon formaldehyde vapors permeate the skirts.After 60 minutes in this atmosphere, the skirts are removed. Neither areduced Wool odor nor a formaldehyde odor can be detected in the skirts.

EXAMPLE VII The fabric of Example I is padded to 70% pick-up of anaqueous solution containing 6.0% monoisopropanolamine, 0.12%paraformaldehyde and 0.1% Synowet HR. This solution is obtained byheating the system with stirring to 120 F. to dissolve theparaformaldehyde crystals. After semi-decating by steaming for 1%minutes and vacuum pumping for 3 minutes, the fabric is wound onto thespindle of a package dye machine and placed in the machine. The machineis then sealed and the pressure therein is reduced to 60 mm. Hg. Intothe evacuated machine is introduced an amount of S gas chemicallyequivalent to the monoisopropanolamine previously padded into thefabric, plus an amount calculated to fill the voids in the cylinder andfabric. This is accomplished by feeding S0 into the machine at a rate of2 liters/ minute for 5 minutes.

After the pressure reaches atmospheric and the temperature reaches 140F., air is forced through the autoclave to remove unreacted $0 if any,after which the fabric is removed from the machine.

Dry crease ratings of 3.2 are obtained with no characteristic reducedwool odor. A fabric similarly treated but without paraformaldehydedissolved in the treating solution is characterized by a heavy reducedwool odor.

EXAMPLE VIII The procedure of Example VII is repeated except that afterS0 is introduced into the machine, the pressure is decreased to 60 mm.after which the resulting partial vacuum is broken with air. The machineis then held at 71 cm. partial vacuum for minutes and the fabric removedand tested as before. Dry crease ratings of 4.0 are obtained and, again,no characteristic reduced wool odor is noticed.

EXAMPLE IX The procedure of Example VII is repeated except that S0 isblown through the fabric at 2 liters per minute for 5 minutes withoutprevious evacuation of the machine. The fabric is permitted to stand inthe SO -laden machine for 5 minutes, after which air is blown throughthe fabric for 30 minutes. Dry crease ratings of 2.7 are obtained withno trace of odor in the fabric.

EXAMPLE X The procedure of Example IX is repeated except that 1.0%Synsoft-LS polyethylene softener is added to the pad solution. Drycrease ratings of 3.2, with no reduced wool odor detectable, areobtained.

l 2 EXAMPLE XI The fabric of Example I is treated with the pad solutionof Example X, semi-decated as in Examp e VII and sealed into a packagedye machine. At a rate of 2 liters/ minute, S0 gas is blown through thefabric for 5 minutes. Air is then blown through the fabric for 5minutes, after which ammonia and air are blown through the fabric untilair leaving the machine is neutral. Dry crease ratings of 3.7 areobtained in this manner, with only very slight reduced wool odor in thefabric. No S0 or NH; odor is detected.

A control fabric similary treated but without paraformaldehyde in theoriginal solution is characterized by a moderate reduced wool odor.

EXAMPLE XII The bisulfite addition product of aqueous formaldehyde andsodium metabisulfite (sodium formaldehyde bisulfite), is added, whereindicated, to various aqueous pad solutions as set forth in Table III.Samples of the fabric of Example I are padded to 100% pick-up with thesesolutions and dried at 200 F. unless otherwise specified.

Odor evaluations are made before and after creasing of the samples on aHoffman press without prior water spraying. The dry crease ratings andodor evaluations are given in Table III.

TABLE III Drying tempera- Odor ature, Dry Pad solution F. crease BeforeAfter 1. Untreated control 1.0 None None. 2. 5% monoisopropanolamine 2004. 3 Heavy Heavy.

sulfite plus 0.1% Syn-Fae 905.

3. 1% sodium formaldehyde 200 4. 0 None.. None.

bisulfite plus solution of No. 2. 4. 2% sodium formaldehyde 200 4 0...do D0.

bisulfite plus solution of No. 2. 5. 5% sodium formaldehyde 200 4 0 -doDo. bisullite plus solution of No. 2. 6. 8.1% sodium tormalde- 2.3.-do-.. Do.

hyde bisulfite. 7. D0 200 1.5 do... Do. 8. 8.1% sodium formalde- 3.9 doVery hyde bisulfite plus 20% slight. ethylene glycol. 9. D0 200 2. 2Slight. Olly.

10. 8.1% sodium formalde- 4. 7 None. None.

hyde bisulfite plus 20% ethylene glycol plus 6.4% monoethanolaminesulfite. Do 200 2.8 Very Do.

slight. 5O

1 Room temperature.

EXAMPLE XIII Dimethylolethanolamine sulfite is prepared by reacting 60grams of paraformaldehyde with 61 grams of ethanolamine at 50-70 C.After cooling and filtering through glass wool, the reaction mass issaturated with S0 gas while being maintained cool with an ice bath. Theresulting product is added (2%) to an aqueous solution containing 5%monoisopropanolamine sulfite and 0.1% Syn- Fac 905. The fabric ofExample I is padded to pick-up with this solution and dried at 200 F.

The fabric is then creased on a Hoffman press without prior waterspraying. Excellent creases, which are durable to subsequent wetting,are produced in this manner and only a very slight reduced wool odorremains in the fabric.

Similar results are obtained with dimethylolisopropanolamine sulfitewhich may be produced by substituting 75 grams of isopropanolamine forthe ethanolamine in the above procedure.

EXAMPLE XIV N-methylolformamide is produced by reacting 30 grams ofparaformaldehyde with 45 grams of formamide 13 at 120-150 C. Aftercooling, the resulting product is mixed in equal parts withmonoisopropanolamine sulfite. Thirteen (13) grams of this mixture areblended with 30 grams of ethylene glycol, after which 67 grams of theglycol are added. After stirring to insure complete dissolution, theresulting solution is padded to 100% pick-up onto the fabric of ExampleI. Again, excellent dry creases are obtained with little or nonoticeable reduced wool odor.

EXAMPLE XV The fabric of Example I is padded to 100% pick-up with anaqueous solution containing 4.5% monoisopropanolamine sulfite, 1.5%paraformaldehyde, 0.1% Syn- Fao 905 and 7.2% urea.

The fabric is dried at 200-225 F. and semi-decated on a Hoffman press atseconds steam followed by 60 seconds vacuum while contained between twopieces of decater fabric.

This fabric, weighing 1482 grams, is then rolled onto the beam of alaboratory gas treating machine, placed in the machine and heated to 140F. Ammonia gas (2.6 grams) is added to the system and circulated for sixminutes. The excess ammonia is vented to the outside. Sulfur dioxide gas(51.4 grams) is then added to the system and, after complete addition,is circulated for six minutes. The excess sulfur dioxide gas is ventedto the outside.

Additional ammonia (1.3 grams) is then added to the system andcirculated for six minutes. A final venting and exhausting is conductedfor 10 minutes. The fabric is removed from the machine and tested.

The initial dry crease rating is 3.5. This rating after ageing at roomconditions for one (1) week, increased to 4.3.

No reduced wool odor is noticed.

The process of this invention may be utilized in any process involvingthe use of reducing agents to modify the characteristics of keratinfibers. A most surprising area of utility is in the presensitizingfield. As noted previously, aldehydes, particularly formaldehyde,inhibit presensitization. Consequently, it is most surprising thatconfigurations can be obtained which are as good as, or better than,configurations obtainable when aldehydes are not utilized. This isparticularly true when the reducing agent and formaldehyde are appliedto the keratin fibers from a single solution, or at least are present inthe fabric simultaneously during setting. This phenomenon may beexplained by the fact that the aldehyde may not react with the keratinfiber until after setting has occurred. The aldehyde may then react toeliminate any further propensity for durable setting. This propensityhas been known to manifest itself in a crease-removing manner. Sincethis propensity would no longer exist under this theory, the resultingcrease performance would be enhanced. It is to be understood, however,that there is no apparent explanation for the phenomenon whereby theodor of reduced wool is substantially minimized by treatment with thecompounds of this invention.

That which is claimed is:

1. In the process of setting garments containing keratinic fibers with areducing agent comprising (a) contacting a fabric containing keratinicfibers with a solution of a reducing agent,

(b) drying to produce a presensitized fabric,

(c) preparing a garment from said presensitized fabric,

and

(d) setting said garment in a given configuration by heating, theimprovement which comprises adding a formaldehydegenerating compoundselected from the group consisting of methylol amides and methylolamines to said solution of a reducing agent to generate formaldehydeduring said setting procedure for the purpose of substantiallyminimizing any reduced keratin fiber odor.

2. The improvement of claim 1 wherein a keratinic fiber swelling agentis added to the solution containing the reducing agent and theformaldehyde-generating compound.

3. The improvement of claim 2 wherein the keratinic fiber swelling agentis urea.

4. The improvement of claim 2 wherein a low molecular weight polyhydroxycompound is substituted for said swelling agent.

5. The improvement of claim 4 wherein the low molecular weightpolyhydroxy compound is ethylene glycol.

References Cited UNITED STATES PATENTS 2,351,718 6/1944 Speakman 8127.62,508,713 5/1950 Harris et al. 8127.6 2,806,762 9/1957 Ramirez et al.8127.5 2,870,041 1/1959 Waddle et al. 8-1163 X 2,983,569 5/1961 Charle8127.5 3,051,544 8/1962 Wolf et al. 8128 3,151,439 10/1964 Dusenbury8-127.6 2,740,727 4/ 1956 Littleton 8128 FOREIGN PATENTS 443,359 2/1936Great Britain.

OTHER REFERENCES Speakman et al., Journal of the Textile Institute; pp.T627T628 (1958).

Wolfram et al., Journal of the Society of Dyers and Colorists, vol. 76,pp. 169-173 (1960).

DONALD LEVY, Primary Examiner J. CANNON, Assistant Examiner US. Cl. X.R.38-144

